Cut-off-valve mechanism



(No Model.) 2 Sheets-Sheet 1.

A. K. MANSFIELD. GUT-OFF VALVE MEGHANISM.

No. 533,177. Patnted Jan. 29, 1895.

in Jn n at /H 2 sheetssheet 2.

Patented Jan. 29, 1895.

A. K. MANSFIELD. GUT-OFF VALVE MECHANISM.

(No Model.)

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UNTTEE STATES PATENT EETCE.

ALBERT K. MANSFIELD, OF CLEVELAND, ASSIGNOR OF ONE-HALF TO BUCKEYEENGINE COMPANY, OF SALEM, OHIO.

CUT-OFF-VALVE MECHANISM.

SPECIFICATION forming part of Letters Patent No. 533,177, dated January29, 1895. Application filed December 4, 1893. Renewed November 12, 1894.Serial No. 528,554. (No model.)

To ctZZ whom it may concern:

Be it known that I, ALBERT K. 'MANSFIELD, of Cleveland, in the county ofOuyahoga and State of Ohio, have invented certain new andusefullmprovements in Out-OfE-Valve Mechanism for Steam-Engines; and Ido hereby declare the following to be a full, clear, and exactdescription of the invention, such as will enable others skilledin theart towhich it pertains to make and use the same.

My invention relates to improvements in valve-mechanism forsteam-engines; and it consists in certain features 01"\construotion andin combinations of parts hereinafter described and pointed out in theclaims.

This invention consists more especially in an improvement of theconstruction disclosed in United States Letters Patent No. 162,714,dated April 27, 1875, to J. W. Thompson, and in United States Patent No.364,207, to O. W. Barnaby, dated June 7, 1887.

In the accompanying drawings, Figure l is a vertical central andlongitudinal section through a steam-cylinder, valve-chest and valves,illustrating the application of my invention. Fig. 2 is a verticalcentral longitudinal section through the body of the steamchest with thevalves removed, showing, the adjacent portion of the cylinder andexhibiting that side of the steam-chest opposite to the side shown inFig. 1. Fig. 3 is a transverse section, showing the valves in endelevation in position within the steam-chest.

Referring to the drawings, A designates the cylinder that is closed atthe ends by means of heads A, in the usual manner, and is fitted with'apiston, B, secured upon a pistonrod b. Steam is admitted to andexhausted from opposite sides of the piston through ports Ct a in thecylinder-shell at the ends of the cylinder, a reciprocating main valve Dbeing employed to admit steam alternately to opposite sides of thepiston, said valve being actuated, by suitable valve-gear, endwise of avalve-chest O that is rigid with the cylinder, and is closed by a hollowcover or back, 0', to which steam from the boiler is admitted by a pipe(not shown) communicating with an opening, 0 in the outer shell of thecover.

The main valve is of the box or chambered type and is composed of apairof end steam- V chambers d, connected by a longitudinal passage ortubular body (1 and working between equilibrium or balance-rings E inthe inner shell of the valve-chestcover, and faces on the cylindersurrounding the ports a.

Each of the steam-chambers d is provided with a supply-opening d thatcommunicates with spaces in the adjacent equilibrium or balance-ring E,and in the casing of each chamber (1 are provided two delivery-ports dthat lead from the chamber to the seat for said chamber and throughwhich steam passes into the adjacent cylinder-ports a a, when said portsd are brought over the respective ports a a in the traverse of the valvewhen said ports d are not closed by the cut-off valve mechanismhereinafter described.

The interior of the main valve is continuously in communication with thesteam-supply,-and in the reciprocation of the main valve steam isadmitted to and exhausted from the cylinder ports at opposite ends ofthe cylinder, and simultaneously admitted to and exhausted from oppositesides of the piston into the valve-chest which is provided with anoutlet communicating with a condense or exhaust pipe. (Not shown.)

The construction thus far described is substantially the same as thatdisclosed in the Barnaby patent hereinbefore referred to, excepting thatthere are two ports a a in each end of the cylinder-shell, one being abranch port of the other, both of said ports a a connecting with thechamber of the valve-chest, and the main valve is provided with twoports d d as already indicated, leading from each steam-chamber of saidvalve and adapted to open into the adjacent ports a a in the cylinder,and an exhaust-port, space, or passage-way, G, is provided between eachpair of ports a a, said exhaust-space or passage. way being so locatedthat when the outer port of either pair of ports a aexhausts into thechamber of the valve-chest, the other or inner port of said pair ofports shall exhaustinto theadjacent exhaust-space 0r passageway Gaforesaid, as shown at the left'hand at Fig. 1, exhaust-passageways G,of course, being in open relation with the chamber of the valve-chest.

It is the usual practice to so construct and set valves of the classillustrated that they shall properly control the opening and closure ofthe exhausting-cylinder-ports and the opening of the cylinder-portsreceivin g steam, the closure of the latter being effected andcontrolled by a cut-oif-valve working within the 'main valve over thesteam-ports thereof, said cut-off valve being under the control of thegovernor, and traversing over the steam-ports of the main-valve, saidcut-off-valve admitting steam through said ports to the cylinder andcutting off steam earlier or later in the stroke in conformity withvarying conditions of load or pressure, or both, as regulated by thegovernor.

A feature of my invention of great importance consists in soconstructing the cut-offvalve, that, in the unclosed position of saidvalve, steam shall simultaneously pass from the respective steam-chamberof the mainvalve, to the ports leading from said chamber, atfourdifierent points, and, furthermore, in so constructing thecut-off-valve that the aforesaid ports shall be adapted to besimultaneously closed by the cut-off-valve.

The on t-off-valve referred to comprises two' sections .[-I H,substantially alike in construction, connected by one or more bolts,stems 0r rods, H, so as to move coincidently, and reciprocated by acommon valve-stem, H passing freely through the stem, D of themain-valve, said sections of the cut-off-valve, being each provided withtwo internal recesses, chambers or passage-ways h that are open at thebottom to the main-valve faces which surround the ports d d of the mainvalve, and against which said cut-off-valvesections fit.

The seats for cut-off-valvesections H, which seats are formed by theported walls of the steam-chambers of the main-valve, are recessed, asat 61 between the respective pair of ports 01 d to enable steam to passto the outer chamber or passage-way of the respective pair of chambersor passage-ways h of the cut-off-valve-sections in the unclosed positionof the valve. The seats are cut away, as at 01 to enable steam to passto inner chambers h of the valve-sections in the unclosed position ofthe valve. The arrangement of parts is such that the cut-off-valvesections are adapted to simultaneously admit steam to the respectivepair of ports (1 d at four different points, as follows:into the innerport of said pair of ports through the inner passage-way of the pair ofpassage-ways h; to the same port from the space 01 formed between thetwo passageways of the pair of passage-ways h and that is in openrelation with the surrounding chamber in the main-valve; to the outerport of the pair of ports d from space d we recess or chamber d andouter passage-way of pair of passage-ways h, and to the same port 01directly from the surrounding steamchamber in the main-valve, all asindicated by arrows, as shown at the right hand in Fig. 1, and thearrangement of parts is also such that the cut-off-valvesections H arecapable of simultaneously closing, respectively, the adjacent steampassage-ways to the steamcylinder.

The object of the important feature of my invention hereinboforeconsidered, is to provide greater area of ports or passage-ways for thequick admission of steam, or to reduce the necessary travel of thevalve, thereby reducing the force required to overcome the inertia ofstarting the valve from a state of rest at each stroke of the engine, orboth.

By the introduction of exhaust-spaces or passage-ways, G, that arearranged transversely between the main-valve and steamcylinder, it willbe observed that one-half of the exhaust-steam passes from the cylinderthrough inner ports a into said exhaust passage-ways, which alsoconstitutes a feature of no inconsiderable importance. The volume ofexhaust steam being greater at the outer ends of exhaust-passageways, G,than near the middle of the main valve, said passage-ways are enlarged,preferably gradually, toward their outer ends, as shown very clearlyinFig. 3, and the inner cylinder ports a are cored angularly, as shown inthe same figure, to accommodate the aforesaid wedge-shaped exhaustpassage-ways G without necessitating the location of the main-valve-seatfarther from the cylinder bore. Said wedge-shaped passageways arepreferably formed partly in the valve-seat and partly in the valve, asshown.

To prevent slight influences from lifting the cut-off valve-sectionsfrom their seats and prevent the valve-sections from being quicklyforced to their seats by steam-pressure when the valve closes, thecut-off-valve-sections are provided with upwardly oroutwardly-projecting preferably centrally located lugs or members H thatare preferably beveled, as at l1, and engage the corresponding beveledportions of inwardly-projecting lugs or members l on the lids or coversI of the main-valve. By this construction the cut-off valve-sectionscannot easily be lifted from their seats.

The lids or covers of the steam-chambers of the main valve arepreferably secured in place by means of bolts or screws 1 (See Fig. 1.)

Another feature of my invention consists in having the lid or cover ofthe steam-chamber of the main valve, at the stem-end of the latter,shouldered or lipped, as at 1 (see Fig. 1,) over the body of the casingof said chamber. By the construction just described, the strength of theportion of the main valve in question is vastly increased and there isno liability of the end-wall, to which the valvestem is attached, beingpulled out by the pull of the stem, added to the pressure of steam.

Springs K (see Fig. 1) bear against the equilibrium or balance-rings,and serve to give a slight initial force to said rings, the springsbeing suitably mounted upon pins L suitably supported centrally of thebalance-rings, being confined upon said pins below the heads L of thepins, the outer side of said heads being engaged by screws M that extendthrough correspondingly threaded holes in the outer shell of thevalve-chest-cover. The tension of the springs, by means of said screws,may be adjusted as required. It will, therefore, be observed that, by myimproved construction, the springs may be used as an auxiliary forcecapable of easy adjustment from without to aid the balance orequilibrium-rings. I would here remark that the function of said ringsis to hold the main valve to its seat, and their effective force is thesteam-pressure per square inch times the area of the circle whosediameter is the diameter of the outside of the ring. If this forceshould be too small by an amount within the range of the springs, it isobvious that adjustment, by means of the aforesaid screws, will overcomethe difficulty.

What I claim is 1. The combination with a steam-cylinder, steam-chestrigid with the cylinder and the main valve comprising two endsteam-chambers suitably seated within said steam-chest, of a cut-offvalve arranged tooperate endwise of the main-valve, and comprising twosections suitably seated in the two end-chambers of the main-valve,respectively, two ports leading from each of the aforesaid steamohambersof the main-Valve to the seat for said chamber, and two ports leadingfrom said seat and communicating with the cylinder bore,saidlast-mentioned ports being adapted to communicate with the aforesaidports in the main valve, and being adapted to also communicate with thechamber of the steamchest, each of the aforesaid cut-oif-valve-sectionsand seat for said sections being suitably constructed to form fourdistinct passageways to the ports in the seat for said section in theunclosed position of the cut-off-valve, and to be capable ofsimultaneously closing said ports, the arrangement of parts beingsubstantially as and for the purpose set forth.

2. The combination with a steam-cylinder, steam-chest rigid with thecylinder and the main valve comprising two end steam-chambers suitablyseated within said steam-chest, of a cut-off Valve arranged to operateendwise of the main-valve, and comprising two sections suitably seatedin the two end-chambers of the main-valve, respectively, two portsleading from each of the aforesaid steamchambers of the main-valve tothe seat for said chamber, and twoports leading from said seat andcommunicating with the cylinder bore, said last-mentioned ports beingadapted to communicate with the aforesaid ports in the main valve, andbeing adapted to also communicate with the chamber of the steamchest,each of the aforesaid cut-01'1" valve-sections and seat for saidsections being suitably constructed to form four distinct passageways tothe ports in the seat for said section in the unclosed position of thecut-off Valve, and to be capable of simultaneously closing ways beingadapted to communicate with one of the adjacent pair of cylinder-ports,substantially as set forth.

3. The combination with asteam-cylinder, steam-chest rigid with thecylinder and the main valve comprising two end steam-chambers suitablyseated within said steam-chest, of a cut-off valve arranged to operateendwise of the main-valve, and comprising two sections suitably seatedin the two end-chambers of the main-valve, respectively, two portsleading from each of the aforesaid steamchambers of the main valve tothe seat for said chamber, and two ports leading from said seat andcommunicating with the cylinderbore, said last-mentioned ports beingadapted to communicate with the aforesaid ports in the main valve, andbeing adapted to also communicate with the chamber of the steam-- chest,each of the aforesaid valve-sections and seat for said sections beingsuitably constructed to form four distinct passage-ways to the ports inthe seat for said section in the unclosed position of the cutofi-valve,and to be capable of simultaneously closing said ports, and an exhaustspace or passage-way G formed between the casing of each steamchamber ofthe main-valve and the seat for said casing, said exhaust-spaces orpassageways being gradually enlarged toward their outer ends and adaptedto communicate with one of the adjacent pair of cylinder-ports,substantially as set forth.

4. The combination with a steam-cylinder, steam-chest rigid with thecylinder and the main valve comprising two end-steam-chambers suitablyseated within said steam-chest, of a cut-off-valve arranged to operateendwise of the main-valve, and comprising two sections suitably seatedin the two end'chambers of the main-valve, respectively, two portsleading from each of the aforesaid steamchambers of the main-valve tothe seat for said chamber, and two ports leading from said seat andcommunicating with the cylinderbore, said last-mentioned ports beingadapted to communicate with the aforesaid ports in the main valve, andbeing adapted to also communicate with the chamber of the steamchest,each of the aforesaid valve-sections and structed to form four distinctpassage-ways to the ports in the seat for said section in the unclosedposition of the cut-offvalve, and to be capable of simultaneouslyclosing said ports, an exhaust-space or passage-way G formed between thecasing of each steamchamber of the main-valve, and the seat for saidcasing, said exhaust-spaces or passageways being gradually enlargedtoward their outer ends and adapted to communicate with one of theadjacent pair of cylinder-ports, and said cylinder-port being coredangularly to seat for said sections being suitably conaccommodate theaforesaid Wedge-shaped exhaust passage-ways without necessitating thelocation of the main-valve-seat farther from the cylinder-bore,substantially as set forth.

5. The combination with a suitably ported steam-cylinder, valve-chestrigid with said cylinder, and main valve arranged to operate in saidchest and suitably ported, of the cutoff valve suitably seated in themain valve, the cut-off valve having one or more centrallylocated lugsor projecting members and the main valve, on its lid or lids, carryinglugs or projecting members engaging said lugs or members on thecutoff-valve, substantially as set forth.

6. The main valve having a steam-chamber

